TabCtrl_SetItemExtra macro (commctrl.h)

Sets the number of bytes per tab reserved for application-defined data in a tab control. You can use this macro or send the TCM_SETITEMEXTRA message explicitly.

Syntax

BOOL TabCtrl_SetItemExtra(
   HWND hwndTC,
   int  cb
);

Parameters

hwndTC

Type: HWND

Handle to the tab control.

cb

Type: int

Number of extra bytes.

Return value

Type: BOOL

Returns TRUE if successful, or FALSE otherwise.

Remarks

By default, the number of extra bytes is four. An application that changes the number of extra bytes cannot use the TCITEM structure to retrieve and set the application-defined data for a tab. Instead, you must define a new structure that consists of the TCITEMHEADER structure followed by application-defined members.

An application should only change the number of extra bytes when a tab control does not contain any tabs.

Requirements